Magnetic disks or hard disks (HD) are used in, e.g., PC storing devices, portable electronic devices, or in-vehicle devices. Recently, applications of these disks have greatly expanded, and surface recording density has improved dramatically.
An electron beam mastering technique has been widely studied for manufacturing a hard disk with such a high recording density. In an electron beam drawing and exposure apparatus, an electron beam spot emitted from an electron gun and converged using an electron lens is irradiated onto a substrate coated with a resist. A blanking control system and a beam deflection control system control the irradiation position of such an electron beam spot to draw a desired beam pattern. For example, an electron beam drawing apparatus has been developed as a device for fabricating a master disk for a recording medium such as an optical disc, as mentioned, for example, in Japan Laid-open Patent Publication No. 2002-367178.
Therefore, drawing by an electron beam with high recording density requires highly precise control of the irradiation position of an electron beam spot. For a hard disk, a concentric pattern is used rather than the spiral pattern employed for an optical disc, for example. An electron beam recording apparatus capable of drawing concentric circles with high precision and having excellent control is important when drawing an electron beam pattern in concentric circles.
There is a need for a controller and a control method for an electron beam recording apparatus capable of control having high precision and a high degree of freedom.